Random spectrum load sequencer and controller



Sept. 10, 1963 r R. FRIEDMAN ETAL 3,103,118

RANDOM SPECTRUM LOAD SEQUENCER AND CONTROLLER Filed Dec. 28, 1961 5 Sheets-Sheet 1 IN VEN TOR. I a fife/mag W Mar/n2! 5. $5? @/a p 0 1963 FRIEDMAN ETAL 3 ,103,118

RANDOM SPECTRUM LOAD SEQUENCER AND CONTROLLER Filed Dec. 28, 1961 3 Sheets-Sheet 2 3 Sheets-Sheet 5 R. FRIEDMAN EI'AL Sept. 10, 1963 RANDOM SPECTRUM LOAD SEQUENCER AND CONTROLLER Filed Dec. 28, 1961 (ML LMW United States Patent RANDOM SPECTRUM LOAD SEQUENCER AND CUNTRULLER Richard Friedman, 8276 Fayette St; Joseph Rudniclr,

7710 Fairl'ield St; and Maurice S. Rosenieid, 8133 Willliams Ave., all of Philadelphia, Pa.

Filed Dec. 28, 1961, Ser. No. 162,997 3 Claims. (Cl. 73-83) (Granted under Title 35, US. (Zode (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to novel and improved random selection apparatus and more particularly to novel and improved apparatus for controlling the load limits applied to an aerofoil structure or the like in a random manner during repeat load tests.

In the test and design of various types of aerofoil structures and the like it is often desirable to simulate the stresses and strains of actual flying conditions on the structure. When this is done, it becomes possible to determine under what conditions and at what point a structural failure may occur. Although various types of random load selection apparatus has been employed in the past, considerable difliculty has been experienced heretofore in providing suitable apparatus which is relatively simple in design and construction and yet fully reliable in operation.

It is therefore a principal object of the present invention to provide novel and improved apparatus for successively selecting any of a plurality of predetermined conditions in a random manner.

It is a further object of the present invention to provide novel and improved apparatus for applying repeat test loads of random magnitude to a structural device.

It is \a further object of the present invention to provide novel and improved apparatus for controlling the load limits successively applied to an aerofoil structure in random manner whereby actual flight load conditions are simulated.

Other objects and many of the attendant advantages 'of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIGURES 1a and 1b when placed side by side provide a diagrammatic view of a preferred embodiment of the present invention;

FIGURE 2 is a cross-sectional view of the sequencer mechanism shown in FIGURE 1;

FIGURE 3 is a cross-sectional view of the V-shaped channel member taken as indicated by line 33 in FIG- URE 2; and

FIGURE 4 is a cross-sectional view of the relay switching device taken as indicated by line 44 in FIGURE 3.

A preferred embodiment of the present invention is illustrated in FIGURE 1 of the drawing. As shown therein, control relays 3, 5, 7, 9, and 11 are energized by circuits which extend from the 115 volt power supply line 13 through manual switch 15, through the upper contacts of the armatures A of preceding control relays respectively through the random ball operated switches 17, 19, 21, 23, and 25, respectively through the control relays, and through the upper contact 27 of relay 3b to ground. Counters 29, 31, 33, 35 and 37 are respectively connected in parallel with relays 3, 5, 7, 9 and 11. When armature 39 of relay 30 engages its lower contact 41, the cycle counter 43 is connected between power supply line 13 and ground. Energization of relay 3% is con- "ice trolled by a circuit that extends from the 8 volt power supply line 45 through the dynamometer micro-switchin g mechanism 47, through the parallel arrangement of armatures ,B of relays 3, 5, 7, 9131111 11 and through relay 30 to ground.

As will :be more apparent herinafter, the valve mechanism 49 controls the flow of air or other suitable fluid from the fluid pump 51 through valve 53 to the jack mechanism 57. Piston 59 of the jack is mechanically connected to the structure 61 which is to be subjected to the repeat-load test in any suitable manner such as by the link system 63 shown in the drawing. The cylinder 65 of the jack is secured to one end of the dynamometer 67 and the other end of the dynamometer is anchored to the ground as at 69. Valve 49 is controlled by the split winding solenoid or the like 71. Winding 71a of solenoid 71 is energized by a circuit that extends from the 8 volt power supply line 45 through the lower limit switch 73 of the dyn-amometer micro-switching mechanism 47, through the parallel arrangement of energized air-matures C of relays 3, 5, 7, 9 and 11, and through winding 71a to ground. Winding 71b of solenoid 71 is energized by a circuit that extends from the 8 volt power supply line 45 through the upper limit switch 75, 77, 79, 81 or 83 of the dynamometer micro-switching mechanism 47, through the parallel arrangement of energized armature B of relay 3, 5, 7, 9 or 11, and through winding 71b to ground.

As best shown in FIGURE 2 of the drawing, the valve mechanism 85 controls the flow of air or other suitable fluid from the source of air pressure 87, through valve 89 to the shuttle operating mechanism 91. Piston 93 of the shuttle operating mechanism is mechanically connected to the shuttle 95 which is disposed in its cylinder 97 so as to reciprocate between a retracted position where the aperture 99 in the shuttle is aligned with the tubular extremity 101 of the hopper 103, and an advanced position where the shuttle aperture 99 is aligned with a suitable opening 105 at the top of the downwardly inclined V-shaped channel member or the like 107. Steel balls or the like 109 of five or any other suitable number of difierent diameters and of any suitable quantity are located inside the hopper 103. The balls 109 are preferably agitated by the mechanism 111 in any suitable manner such as by means of the bevel gears 113 and 115 and the motor 117. Switches 17, 19, 21, 23 and 25 \are mounted as shown on the side wall 129 of channel member 107 at predetermined points therealong such that each ball having a given diameter actuates one said switch as it drops from atop the diverging upper edges 131 and 133 into the channel therebetween. Any suitable receptacle or the like 135 is positioned adjacent the lower extremity of the V-shaped channel member 107 to receive the various balls after they have dropped from the V-shaped upper edges of the channel member 1117 and actuated switch 17, 19, 21, 23 or 25.

The valve mechanism 85 for shuttle 95 is controlled by the split winding solenoid or the like 137. Winding 137a of solenoid 137 is energized by a circuit that extends from the 8 volt power supply line 45 through the lower limit switch 73 of the dynamometer micro-switching mechanism 47, and through winding 137a to ground. Winding 13712 of solenoid 137 is energized by a circuit that extends from the 8 volt power supply line 45 through the upper limit switch 75, 77, 79, 81 or 83 of the dynamometer micro-switching mechanism 47, through the parallel arrangement of energized armature B of relay 3, 5, 7, 9 or 11, and through winding 137b to ground.

Indicator lamps 139 and 141 :are preferably respectively connected as shown between the 8 and 115 volt power supply lines and ground.

The multiple-load-limit dy namometer '67 with its microswitching mechanism 47 is of conventional design. By itself it forms no part of the present invention. For the sake of simplicity, therefore, a detailed description of its construction is not provided herein. For a complete understanding of the present invention, it need only be understood that when substantially no load is applied across the dynamometer only its lower limit switch 73 is closed and when the load increases its upper limit switches 75, '77, 79, 8 1 and 83 successively close.

In operation, the dynamometer is first calibrated on a suitable testing machine and the desired variable upper load limits are set by appropriate adjustment of the micro-switching mechanism 47. Steel balls or the like 1139 of the proper size and quantity are then placed in the hopper 103. The pump 51 which develops the required air pressure is started, and the motor 117 for agitating and mixing the balls is energized. Assuming the shuttle is initially in its retracted position, one of the balls 109 in the hopper 103 drops into the aperture 99 in the shuttle. Winding 137a of solenoid 137 is immediately energized by the circuit that extends from the 8 vol-t power supply line 45 through the lower limit switch 73 of the dynamometer micro-switching mechanism 47 and through winding 137a to ground. When this occurs, the shuttle 95 is operated to its advance position where the ball in aperture 99 drops into the upper edges of the V-shaped channel member 107. The ball then r-olls down the incline to a point where the diverging side walls of channel member 137 allow it to drop within the channel member and actuate switch 17, 19, 21, 23 or 25. When this occurs, relay 3, 5, 7, 9 or 11 and its associated counter 29, 31, 33, 35 or 37 are energized. Armature A of relay 3, 5, 7, 9 or 11 then engages its lower contact and relay 3, 5, 7, 9 or 11 remains energized through a stick circuit that extends from the 115 'volt power supply line 13 through armature A of the relay, through the relay itself and through the deenergized armature 39 of relay 29 to ground. When armature C of relay 3, 5, 7, 9 or 11 engages its lower contact, the lower limit switch 73 of the dynamometer micro-switching mechanism being closed, winding 71a of solenoid 71 is energized, valve 49 moves to its lowermost position in its cylinder, air pressure begins to build up, and an increasing load is applied to the structure 61. Armature B of relay 3, 5, 7, 9 or 11 also engages its lower contact and thereby preconditions the upper load limit circuit for energization. When the upper limit dynamometer switch which is in series with armature B of energized relay 3, 5, 7, 9 or 11 is closed, winding 71b of solenoid 71 is energized, valve 49 returns its uppermost position in its cylinder, and the load applied to the structure 61 by jack 57 is dissipated. Simultaneously, winding 13711 of solenoid 137 is also energized and the shuttle 95 is operated to its retracted position. Relay 30 is also energized, the stick circuit of relay 3, 5, 7, 9 or 11 is deenergized and the cycle counter 43 is pulsed. When the load across the dynamometer 67 is fully dissipated, winding 137 of solenoid 137a is energized, the shuttle is operated to its advanced position and the entire cycle is repeated.

It will be noted that, inasmuch as each ball is eliminated from the system after it is deposited in the receptacle 135, the probability of energization of each of the relays 3, 5, 7, 9 and 11 changes. It has been found that this continuous change iacilitates more eifective comparison of test results in the laboratory.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that 'within the scope of the appended claims the invention may be practiced otherwise than .as specifically described.

What is claimed is:

1. Apparatus for simulating flight load conditions on an aerofoil structure said apparatus comprising a receptacle; a plurality of balls having a predetermined number of unique diameters disposed within the receptacle; an inclined channel member, said channel member being positioned and constructed such that its side walls extend upwardly and diverge one from the other; means tor successively selecting a ball at random from the receptacle and positioning it atop the diverging side walls of the channel member; a plurality of switch actuated relays disposed adjacent said channel member at points therealong such that as each ball having a different diameter drops into the channel member a different relay is energized; and means for applying a unique maximum load to the structure when each said relay is energized.

2. Apparatus for simulating fiight load conditions on an aerofoil structure said apparatus comprising a hopper; a plurality of balls having a predetermined number of unique diameters disposed within the hopper; means for agitating the balls within the hopper; an inclined channel member, said channel member being positioned and constructed such that its side walls extend upwardly and diverge one from the other; means for successively selecting a ball at random from the hopper and positioning it atop the diverging side walls of the channel member; a plurality of switch actuated relays disposed adjacent said channel member at points therealong such that as each ball having a different diameter drops into the channel member a different relay is energized; and means for applying a unique maximum load to the structure when each said relay is energized.

3. Apparatus for simulating flight load conditions on an aerofoil structure said apparatus comprising a hopper; a plurality of balls having a predetermined number of unique diameters disposed within the hopper; means for agitating the balls within the hopper; an inclined channel member, said channel member being positioned and constructed such that its side walls extend upwardly and diverge one. from the other; means for successively selecting a ball at random from the hopper and positioning it atop the diverging side walls of the channel member; a plurality of switch actuated relays disposed adjacent said channel member at points therealong such that as each ball having a different diameter drops into the channel member a difierent relay is energized; means for applying load to thestructure; and means responsive to the energizati-on of each relay for controlling a unique maximum load applied to the structure.

References Cited in the file of this patent v UNITED STATES PATENTS 1,166,537 Neal Jan. 4, 1916 1,366,130 Mueller Jan. 18, 1921 2,734,604 Soave Feb. 14, 1956 3,022,662 Hebeler Feb. 27, 1962 

2. APPARATUS FOR SIMULATING FLIGHT LOAD CONDITIONS ON AN AEROFOIL STRUCTURE SAID APPARATUS COMPRISING A HOPPER; A PLURALITY OF BALLS HAVING A PREDETERMINED NUMBER OF UNIQUE DIAMETERS DISPOSED WITHIN THE HOPPER; MEANS FOR AGITATING THE BALLS WITHIN THE HOPPER; AN INCLINED CHANNEL MEMBER, SAID CHANNEL MEMBER BEING POSITIONED AND CONSTRUCTED SUCH THAT ITS SIDE WALLS EXTEND UPWARDLY AND DIVERGE ONE FROM THE OTHER; MEANS FOR SUCCESSIVELY SELECTING A BALL AT RANDOM FROM THE HOPPER AND POSITIONING IT ATOP THE DIVERGING SIDE WALLS OF THE CHANNEL MEMBER; A PLURALITY OF SWITCH ACTUATED RELAYS DISPOSED 